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1.
微波遥感的发展与应用   总被引:2,自引:0,他引:2  
微波遥感作为遥感技术的一个分支,是20世纪70年代发展起来的一门年轻的学科.着重以我国微波遥感发展的历程为例,回顾了三十多年来微波遥感领域学术与技术的迅速发展,比较分析了微波遥感对于可见光和红外遥感有着不可比拟的优越性,因而在海洋、冰雪、大气、测绘、农业、灾害监测等方面都有着广泛的应用.同时提出了目前我国在微波遥感领域存在的若干不足并指出了今后的研究方向.  相似文献   

2.
A series of dynamic behavior tests on Nanjing flake-shaped fine sand were performed by using the WFI cyclic triaxial apparatus made in England. The dynamic behaviors of Nanjing flake-shaped fine sand under different static deviator stress levels and cyclic stress ratios were studied. Through comparing the effective stress path under cyclic loading with static loading, the processes of liquefaction of saturated Nanjing flake-shaped fine sand with development of dynamic pore-water pressure, including the initial compact state, compression state and dilative state, were investigated. The variation of the shear stiffness with the number of cycles and cyclic strain was investigated by analyzing the secant shear modulus in each unload-reload loop of dynamic stress-strain relationship. And by means of the exponential function, the empirical equations of the relationship between secant shear modulus Gsec, shear modulus ratio Gsec/Gmax and cyclic strain ε were established based on series of test results. The results show that according to different combinations of static deviator stress and cyclic stress, two kinds of failure patterns with deviator stress reversal or no deviator stress reversal are observed in the samples tested in this series, including cyclic mobility and the failure of accumulation residual strain. In addition, the degradation of dynamic shear modulus is due to the development of vibration pore-water pressure and it is observed that the shear modulus reduces with the progressive number of cycles.  相似文献   

3.
Against the background of the sand-flow foundation treatment engineering of Guangzhou Zhoutouzui variable cross-section immersed tunnel, a kind of sand deposit-detecting method was devised on the basis of full-scale model test of sand-flow method. The real-time data of sand-deposit height and radius were obtained by the self-developed sand-deposit detectors. The test results show that the detecting method is simple and has high precision. In the use of sand-flow method, the sand-carrying capability of fluid is limited, and sand particles are all transported to the sand-deposit periphery through crater, gap and chutes after the sand deposit formed. The diffusion range of the particles outside the sand-deposit does not exceed 2.0 m. Severe sorting of sand particles is not observed because of the unique oblique-layered depositing process. The temporal and spatial distributions of gap and chutes directly affect the sand-deposit expansion, and the expansion trend of the average sand-deposit radius accords with quadratic time-history curve.  相似文献   

4.
The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on single piles with different forms of pile shoes and on their composite foundations were analyzed. The distribution patterns of axial force, shaft friction and toe resistance were studied based on the measurements taken from buried strain gauges. From the point of engineering application, the pile has merits in convenient quality control, high bearing capacity and reliable quality, showing higher reasonability, advancement and suitability than other ground improvement methods. The pile can be adopted properly to take place of ordinary ground improvement method, achieving greater economical and social benefits.  相似文献   

5.
长于论辩,是《孟子》散文的突出特征.《孟子》一书通过对孟子言行的记录,不仅表现了孟子的思想和理论,亦成功地为后人展示了一个鲜活的辩者形象.孟子与时人的论辩涉及政治、经济、伦理道德、哲学等诸多领域;通过对旁征博引、因势利导、诱敌入彀、归谬反驳、执经行权等论辩方法的娴熟驾驭,表现出鲜明的个性特点.  相似文献   

6.
克里斯蒂娜一生孤独迷离,她弃绝人间的舒适享乐全心追求永恒的精神快乐.诗歌是她生活的真实写照:从初恋失败,父亲病逝,到中年全方位的社交活动,再到孤独的晚年隐退.她的诗歌也呈现出统一协调的三部曲:从温婉细腻的抒情诗,到内涵丰富的叙事诗,再到热烈苍凉的祈祷文.爱是诗人背后最隐秘的缘由.为寻求心灵的平静,她试图在爱中找到永恒,却一次次被爱推着向前走:从人世爱恋到社会爱心,再回归上帝.  相似文献   

7.
Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.  相似文献   

8.
一种风幕式抽油烟机的实验研究   总被引:3,自引:1,他引:2  
通过对厨房油烟扩散机理的分析和模型实验,研究了影响油烟控制的各种因素,采用实验与计算流体力学仿真技术相结合的方法,对不同情况下油烟罩的油烟控制性能进行了比较、分析,设计出了一种新型节能型抽油烟机。  相似文献   

9.
Creep tests under at a certain temperature and different stress levels were performed on two carbon constructional quality steels at a certain stress level and different temperatures,and their creep curves at high temperature were obtained based on analyzing the testing data.Taking 45 steel at a certain temperature and stress as the example,the integral creep constitutive equation and the differential stress-strain constitutive relationship were established based on the relevant rheological model,and the integral core function was also obtained.Simultaneously,the viscous coefficients denoting the viscous behavior in visco-plastic constitutive equation were determined by taking use of the creep testing data.Then the viscous coefficients of three carbon steels(20 steel,35 steel and 45 steel) were compared and analyzed.The results show that the viscosity is different due to different materials at the same temperature and stress.  相似文献   

10.
In order to optimize plastic viscosity of 18 mPa·s circulating micro-bubble drilling fluid formula,orthogonal and uniform experimental design methods were applied,and the plastic viscosities of 36 and 24 groups of agent were tested,respectively.It is found that these two experimental design methods show drawbacks,that is,the amount of agent is difficult to determine,and the results are not fully optimized.Therefore,multiple regression experimental method was used to design experimental formula.By randomly selecting arbitrary agent with the amount within the recommended range,17 groups of drilling fluid formula were designed,and the plastic viscosity of each experiment formula was measured.Set plastic viscosity as the objective function,through multiple regressions,then quadratic regression model is obtained,whose correlation coefficient meets the requirement.Set target values of plastic viscosity to be 18,20 and 22 mPa·s,respectively,with the trial method,5 drilling fluid formulas are obtained with accuracy of 0.000 3,0.000 1 and 0.000 3.Arbitrarily select target value of each of the two groups under the formula for experimental verification of drilling fluid,then the measurement errors between theoretical and tested plastic viscosity are less than 5%,confirming that regression model can be applied to optimizing the circulating of plastic-foam drilling fluid viscosity.In accordance with the precision of different formulations of drilling fluid for other constraints,the methods result in the optimization of the circulating micro-bubble drilling fluid parameters.  相似文献   

11.
从解构主义的视角出发,先叙述和分析了原文和译文的关系,随后又分析了原文作者与译者的关系。虽然解构主义翻译理论颇受责难,但却也有其可取之处,并且在翻译领域,它的正面影响要大于其负面影响。  相似文献   

12.
加强专业建设 提高人才培养质量   总被引:1,自引:0,他引:1  
专业建设是高等学校重要的教学基本建设,对高等学校的改革与发展具有深远影响。对我校专业建设中如何坚持特色与优势专业的建设、构建“大包装”专业群的经验进行了介绍,并就专业建设中应进一步加强的几个方面进行了探讨。  相似文献   

13.
专业建设是高等学校重要的教学基本建设,对高等学校的改革与发展具有深远影响.对我校专业建设中如何坚持特色与优势专业的建设、构建"大包装"专业群的经验进行了介绍,并就专业建设中应进一步加强的几个方面进行了探讨.  相似文献   

14.
加速经济增长,力争实现我国经济隔几年上个台阶是实现社会主义现代化的客观要求。然而由于存在高消费需求与低消费能力、高消费渴望与消费信心不足、巨大的消费潜力与不良的消费环境等矛盾,制约了社会经济的发展。因此,增加收入以提高消费能力、培养成熟的消费观念、增加有效供给、改善消费环境、完善社会保障制度就成为消除消费矛盾,促进经济发展的必然选择。  相似文献   

15.
制度性推进高校图书馆创新与发展   总被引:2,自引:0,他引:2  
知识经济的本质在于创新,教育创新体系下高校图书馆亟需创新.领域及制度方面包括战略创新;服务方式创新;管理机制创新;技术创新等.建设性提出共建协作创新,重组后融资方略创新尝试.论证了知识经济时代应处理把握好创新人才的培养和造就、学科建设和图书馆地位等三者间的关系.  相似文献   

16.
对科技期刊的改革进行了探讨,对校企联合办刊的必要性和可行性进行了调查、分析,提出了校企联合办刊是科技期刊改革创新的新方法。  相似文献   

17.
垂直裂缝井重复压裂前原地应力场变化研究   总被引:1,自引:0,他引:1  
重复压裂裂缝起裂和延伸机理是重复压裂研究的重点和难点,初次人工裂缝和生产诱导是应力变化的两个主要原因。研究引起垂直裂缝井重复压裂前原地应力场变化的主要因素,认为重复压裂应优先选择有潜力的未动用小层进行补孔压裂,设计时应充分考虑裂缝的长度及导流能力,以获得更大的泄油面积,使老井获得更好的增产效果。  相似文献   

18.
通过对地震造成的危害的分折 ,使人们真正认识到建筑工程抗震的必要性和重要性 .分析了混合结构在抗震构造设置、施工质量方面存在的问题 ,就此提出了几点看法  相似文献   

19.
从城乡一体化建设与新农村建设的需要、现有农村社区服务体系状况的角度,分析了政府对农村社区投放的公共服务产品结构性失衡的原因,提出了构建以政府为主导、社会服务组织为主体的农村社区服务体系,推进农村社区由行政管理型向服务管理型转变,逐步完善农村社区管理机制.  相似文献   

20.
论述梳理机用齿条配套设计的极端重要性,提出了齿条配套设计的基本思路,研究了系统评价其梳理效果的模糊分析方法,研究结果为齿条的优化设计和合理选用提供了可靠依据.  相似文献   

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